It has long been customary to affix to merchandise a document which has printed thereof information such as price, stock classification, and other desired information. Recently, there have been developed documents which, in addition to containing the foregoing printed information, are also provided with a magnetizable portion on which is magnetically encoded some or all of the foregoing printed information, plus, if desired, additional information to be used in control of the merchandising operation.
The present invention relates to a machine for marking such documents with both the printed information and also the magnetically encoded information.
In such machines it is desirable that there be provided means for error detection to determine whether the magnetically encoded information, which is of course invisible, has been recorded correctly or not. If an erroneous recording is detected, the erroneously recorded document as operated on by the machine nevertheless has had applied to it the printed information, but some additional error indication is also printed on the document -- either as a color coded mark or a legend of some sort indicating that the document should not be used. However, the printed error indication may be overlooked by the machine operator or other clerical personnel involved in the process of making the documents or applying them to the merchandise. Also, the ink supply for the errorindicating printing means may run dry so that the erroneous document does not contain the error indication. It will therefore be seen that a document marked by the foregoing type of machine may nevertheless be inadvertently applied to the merchandise even though it contains incorrectly recorded magnetic information.